How to activate my iPhone

I got my iPhone 4 yesterday, with a MTN micro sim. I put the sim in the phone and waited 24 hours for the sim to activate. This afternoon when I switched on the phone, it says no service in the left top corner. So I can't do anything with the phone. I phoned MTN, and got transferred and referred all over the place. They say my sim has been active since yesterday, and no one seems to know what the problem is. Any ideas what might be wrong?

I got my iPhone 4 yesterday, with a MTN micro sim. I put the sim in the phone and waited 24 hours for the sim to activate. This afternoon when I switched on the phone, it says no service in the left top corner. So I can't do anything with the phone. I phoned MTN, and got transferred and referred all over the place. They say my sim has been active since yesterday, and no one seems to know what the problem is. Any ideas what might be wrong?

is your old SIM still active?
if yes then the answer is MTN hasn't activated your new SIM as both shouldn't work at the same time.

Some times the internet is so slow, it would be faster to just fly to Google's headquarters and ask them this $h1t in person.!

My phone sometimes shows "No Service" as well, think it's an MTN issue more than it is the sim really. Upgraded to 4S about 3 months ago. Was worried they got the billing wrong or something and cut me off. Restarted the phone and it picked up the signal again. Not sure WTF is going on. At least my comms are usually through my wireless internet